docs: separate custom query documentation into a new file

See merge request gitlab-org/gitlab-vscode-extension!228

This makes the documentation parser sort the CI variables before
comparing a difference.

Fix CI variables update script compares order of items

See merge request gitlab-org/gitlab-vscode-extension!230

ci: add junit reports

See merge request gitlab-org/gitlab-vscode-extension!183

refactor: change git_service to always requrie workspaceFolder

See merge request gitlab-org/gitlab-vscode-extension!233

add commenting range for old files in the MR diff

See merge request gitlab-org/gitlab-vscode-extension!232

We parse the MR version REST API response into hunks. These hunks tell
us what lines have been added in the new file version on the diff.
We then convert these lines in VS Code Ranges and return them as ranges
on which the user might leave a comment.

refactor: reduce eslint warnings

See merge request gitlab-org/gitlab-vscode-extension!217

Thanks to @Musisimaru for noticing that we forgot to put the wrapper in
the list of subscriptions.

We were mistakenly showing the "Could not get Git Extension" message
during every extension startup.

feat: add commenting ranges for new file versions in diff

See merge request !234

docs: update outdated sign up link

See merge request !237

feat: show welcome view when there is no git repository

See merge request !235

docs: add notice to enable fork repo mirroring

See merge request !236

chore: update CI variables

See merge request !238